Fuse tube terminal



1950 c. E. SCHULTHEISS 2,531,949

FUSE TUBE TERMINAL Filed March 22, 1948 2 Sheets-Sheet 2 Patented Nov. 28, 1950 FUSE TUBE TERMINAL Carl E. Schultheiss, Libertyville,

11]., assignor to S & Electric Company, Chicago, Ill., a corporation of Delaware Application March 22, 1948, Serial No. 16,179

This invention relates, generally, to terminals and it has particular relation to terminals for expulsion fuse tubes.

In the fuse constructions shown in Ramsey Patents Nos. 2,108,993 and 2,247,700 and in McMahon Patent No. 2,253,720 fuse links are employed which have rigid anchor contact members or cone terminals that interfit with correspondingly shaped sockets in the terminals at the discharge ends of the fuse tubes. Spring tension is applied to the fuse links in these constructions so that the cone terminals are held in the cone shaped sockets under spring tension to provide low resistance electrical contact with the terminals. In these bayonet type fuse devices or cut cuts the diameter of the housing and the contacts carried thereby as well as the diameter of the fuse tube and its bayonet contacts must be kept at minimum values to make the device economical to manufacture.

It is sometimes the case that it is desirable in the field to employ fuse links for these fuse constructions which are not provided with the rigid anchor contact members or cone terminals and which are furnished by different manufacturers. Also it may be desirable to employ fuse links with or without cone terminals in the fuse tubes in these constructions without employing the spring and cable assembly which is shown as being provided to maintain the fuse link under tension and to withdraw the sleeve of the link within the fuse tube when the link blows.

In Ramsey Patent No. 2,247,700 the lower fuse tube terminal is provided with a clamp member held by a set screw for clamping the flexible conductor of the fuse link to the terminal. However, such a construction is not feasible for the bayonet type of fuse mechanism shown in Ramsey Patent No. 2,108,993 and McMahon Patent No. 2,253,720 because of space limitations, interference with venting resulting in lowering of the interrupting capacity of the cut out and other practical difficulties.

Accordingly, among the objects of this invention are: To provide a terminal construction for the discharge end of an expulson type fuse tube for accommodating fuse links having rigid anchor contact members or cone terminals on the flexible leads and to accommodate fuse links without the rigid anchor contact members or cone terminals on the flexible leads; to employ a single terminal construction for accommodating either type of fuse link and for making connection either to the cone terminal or to the flexible lead as the case may be; to arrange the clamp com 4 Claims. (Cl. 173-269) struction so that it does not interfere with the insertion of the fuse tube in the fuse housing for a bayonet type of fuse device; to construct the clamp mechanism so that it will not interfere with the discharge of the products of the arc resulting from the blowing of the fuse link and will not be damaged by the heat of the arc; to accommodate different makes of fuse links; to provide a construction the removable clamp portion of which is a standard article of commerce that is usually carried on all lineniens trucks rather than a special clamp mechanism which if lost when separated from the remainder of the terminal construction could not be replaced readily; and to provide a solution to the problem of accommodating various types of fuse links in a given fuse tube and terminal design of such dimensions as to permit its interchangeable use within the confines of the insulating housing, such as shown in Patent No. 2,108,993, having no exposed live parts, which has been applied extensively on several electric power systems throughout this country.

Other objects of this invention will, in part, be obvious and in part appear hereinafter.

This invention is disclosed in the embodiment thereof shown in the accompanying drawings and it comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of this invention reference can be had to the following detailed description. taken together with the accompanying drawings, in which:

Figure 1 is a view, in side elevation, of a bayonet type fuse device, such as that shown in Ramsey Patent No. 2,108,993 or McMahon Patent' No. 2,253,720, in which the present invention is incorporated;

Figure 2 is a longitudinal sectional view of the fuse tube which is arranged to be connected to a handle and inserted in the fuse housing shown in Figure 1, the terminal at the discharge end of the fuse tube being constructed in accordance with this invention and having the flexible lead of the fuse link clamped thereto;

Figure 3 is a detailed sectional view at an enlarged scale, taken along the line 33 of Figure 2 and showing a part of the lower portion of the housing shown in Figure 1;

Figure 4 is a view, similar to Figure 2, and

showing how a fuse link provided with a cone terminal can be employed in conjunction with a spring and cable assembly in lieu of the construction shown in Figure 2; and

Figure 5 is a view, similar to Figure 4, showing how the fuse link construction illustrated in McMahon Patent No. 2,253,720 can be employed in conjunction with the present invention where a spring'and cable assembly isemployed.

Referring now particularly to Figure 1 of the drawings, it will be observed that the reference character it designates, generally, a bayonet type out out such as that shown and described in more detail in Ramsey Patent No. 2,108,993. mounted on a cross arm I l or like support. For this purpose a clamp l2 may be providedwhich supports the cut out it by means of a bracket I3. The cut out It! includes a corrugated tubular body or housing M of insulating material such asporcelain.

The cutfout' lee also includes a handle 15. of insulating material, such as! porcelain, and it is arranged to. be threaded onto a terminal whichris located at; the upperendof a fuse tube [1i shown in Figure'z. the fuse. tube. [.1 is formed of: insulating material. For example, it m y have a; liner of'fiber and an outer covering 011a phenolic condensation product. Figure ofzthe drawings the parts are shown full size. H9iWQ' 6: it will be understood that. this is for illustrative: purposes only; and that. various sizes an dlmensiohs; can, be employed depending upon th opera ing conditions.

Within the fusetu'be, i! there may be located afuse; link which isindicated, generally, at all. The; fuse-link 23; may be of the. type shown in Ramsey Patent No... 2,103,993,.although it. will be understood that; other; typesioilfuse links can be employed in practicing; this invention. At its unperiendthe fuse: link zahas a head assembly 21:: which-;bears a ainst the upper end of the terminal IS to provide eleutricaland mechanical onnect on. ther.ewith.v Thew fuse link, 2.8..has a flexible conductor 22L extending from: its, other end. The flexible conductor 22; comprises a large number of small diameter, wires of good condu tin mat rial. LlC JaS copper; It ex.- tendfisligwnwardly through the bore of the fuse tube; [-1, and out, at. the lower discharge end I wh re ar er ina l shown en a ly at 23, s l cated;.; The: term inal. 23 includes; a, ferrule; 24 which is arranged, as shown, to resell/either lower end of; the fuse tube- FL Aepin 25, serves tohold the fer leZAin plaoe on the lower end of the use-tum; i

Ip E-igure13 of thedrawingsthe construction of the terminal 23 is illustrated at double the scale-used inEigure 2.. Itwill' be' obseryedthat the terIn-inal; 23 includes a, semi-circular: tongue 2,6 ;whic;h extends; downwardly from; and. is in: esrelln orme w th he ferrule 2.4.. At its lower end the tongue 26 has an integrally. formed. bifurcated; extension.v 21 which has branches or arms: 2,3;wit-hz a, slot; 29 therebetween through whiohtheflexibleconductor 22 canbe placed as shown inFigures 2 and 3. The extension 21 isthreaded as indicated? at. 30: for receiving a clampnutjBL. The clamp. nut 31 is arranged to move a jaw, 32: which: is Islidably mounted in the slot-.1 29' and which has an arm 33=extending tl irough the nut 3i: from.which.1ugs 34 project for; preventing; separation of. the, jaw 32 from the nut 3|. The nut. 31: and jaw. 32; comprise aiconventional clampnut assembly'which is' em- The cut out H3 is arranged to be J,

ployed for split bolt connectors. These clamp nuts are standard articles of commerce and ordinarily are carried in the truck of a lineman so that a supply of them always is available.

In order to fuse the cut out it, the handle I5 is withdrawn together with the fuse tube H from the housing or body [4. The parts of the previously blown fuse are removed after the fuse tube ll is unscrewed from the handle 15. The clamp nut 3| is removed. A new fuse link 29 then is inserted through the upper end of the fuse tube ii, the flexible conductor 22 being drawn through the lower discharge end of the fuse tube ll until the head assembly 2| rests against the upper end of the terminal H5. The lower end of the flexible conductor 22 then is passed through the slot 29 and located therein as shown in Figure 3. Thereafter the clamp nut 3! is threaded onto the extension 27 with the jaw 32 in the slot 29. The clamp nut Si is tightened so as to securely held the flexible conductor 22in the bottom of the slot2 9. The lineman then cuts the flexible conductor 22- at 35 anddiscards the portion 36 of the flexible-conductor 22.

It will be observed that the tongueZB iS-formed so that it: is offset slightly, as indicated at 31, from. the outer cylindrical s'urfaee of the ferrule 24.. The: flexible conductor ZZ -can becut -as indicatedat 35 close to the surfaceof the inwardly offset tongue 26 There is then-no difiiculty i n inserting the fuse tube IFWhichhas beeiirefused in the; manner described and attached toi the handle it into the body or housingl l of' the out out l0. This body or housing I 4 is provided with -line terminals, such-'as the line -terminal'sshown in- Ramsey Patent l lo. 2-,108'3993, with which the terminals Hi and ZE-haweele'c} trical contact;- The' lower-terminal-has an'o'utfiared spout 38 which directs the areproductsout of the fuse tube l l and proteets the lower end of the housingl dfromthe'heat-thereof} When the terminal construction 234's employedas described, the fuse tube l l carr beihserted in th'e body or housing Hi with. no interferenc'e being encountered as itis moved into-position through the line terminals and through the-spouted. 7

It will be noted that the threads at are' re moved-from the front sides of the bran'ch'esor arm-s 28 st; that-fiatfaces 'iil, Figures--;2P;an'd 3, are provided along which the are root-013'- heavy faults can move afterthelowerf-use lihk terminal has been expelled; 1 The -removalf of the threads and formation of the faces tEpr-ovi'db sufiicient mechanical clearance so that any fusioir and distor tionof the branches or arms 28 -du'e to the heat of the are will not interferewith subsequent application of the nut Si -as described'E Whenthe fuse linkQZ-tgis' located in' the fuse tube i-l as shown-inF-igure 'ofthedrawihgs} the cut out i [i functionssolely as anexplusion fuse when the link" 2Q blows under overload -condi tions. The interrupting capacity of the cnt-jout Hi "can be improved by employing ;a'- spring and cableassembly which is indicated} generally; at A6 in Figure 4 of thefirawihgs. Thi's is described in more detail in Ramsey Patent no: 2 l089'93. It includesa head 41 which-bears against the upper end of the terminal 161* Depending from the head 41" area coil tension spring fir'z and a flexible conductord 3 whilch-are fastened at: their lower ends to a terminal 44 5 The terminal llr is threaded internally for reeeiving= the externally threaded' terminal' of the fuse link' 2H3 Itisdesirablein-theconstruction=-shown inFig -w ure 4 to provide for tensioning accurately the spring 42. Also it is desirable to properly locate the fuse link 20' in the fuse tube ii. For these purposes a rigid anchor contact member or cone terminal 45 is provided on the flexible conductor 22 as described in Ramsey Patent No. 2,108,993. The spring and cable assembly 48 with the fuse link as attached thereto is inserted through the upper terminal i6 and the fuse tube ll. The flexible conductor 22 extends out of the lower end of the fuse tube l7 andcan be grasped to pull the fuse link 2a! to the position shown in Figure 4 and at the same time to tension the spring 42. The flexible conductor 22 is drawn through the fuse tube l1 sufficiently far so as to permit the cone terminal 415 to be positioned in the slot 29 with the cone portion 5 thereof bearing against the outer ends of the branches or arms 28 of the extension 21. These branches or arms 28 are recessed as indicated at 355 to accommodate the cone terminal 55. After the cone terminal 45 has been positioned in the slot 29 as described so that the reaction of the spring 42 is taken up by the extension 27, the flexible conductor 22 can be cut off as indicated at H.

In Figure 5 of the drawings the fuse link 2%] is constructed as described in more detail in McMahon Patent No. 2,253,720. Specifically the flexible conductor 22 of the fuse link 2:? has a cone terminal 19 which is arranged to receive and hold an indicator '53 of insulating material which, as shown in Figure 1, projects below the insulating housing it of the cut out It. The indicator 5!! is provided to show by its presence that the fuse link 26 has not blown and by its absence that it has blown and should be replaced. When the fuse link blows, the indicator 5i] and the terminal 49 are free to drop to the ground.

It will be noted that the clamp nut 3i and jaw 32, employed as shown in Figures 2 and 3 for gripping the flexible conductor 22, are omitted when the rigid anchor contact members or cone terminals 45 or 49 are employed as shown in Figures 4 and 5 of the drawings. On the other hand the terminal 23 at the discharge end of the fuse tube ll' is constructed so that it can accommodate any of the types of fuse links which are illustrated in the drawings. will be understood that the clamp nupt 3| and jaw 32 may be employed in the construction shown in Figures 4 and 5 of the drawings where the rigid anchor contact members or cene terminals 25 or as are omitted, it being desired to clamp the flexible conductor 22 to the terminal 23 in the manner shown in Figures 2 and 3 and previously described.

It will be observed that the construction of the terminal 23 to accommodate either type of fuse link, i. e., with or without the rigid anchor contact member or cone terminal, is such as not to interfere appreciably with the discharge from the fuse tube ll when the fuse link 26! blows. Furthermore, regardless of the type of fuse link that is employed, there is no obstruction provided by the terminal 23 when either type of fuse link is employed which would prevent or interfere with the insertion of the fuse tube i! into the body or housing is of the cut out ill or its withdrawal therefrom. Moreover, it can be inserted through the spout 38 even though the same has a limited opening therethrough. Since the lineman ordinarily has available a supply of these clamp nuts 3| in his truck, it is unnecessary to stock a supply of specially designed parts for use with the terminal 38 when it is desired to clamp a flexible con- 6 ductor 22 thereto which is not provided with a rigid anchor contact member or cone terminal.

Since certain changes can be made in the foregoing construction and different embodiments of the invention can b made without departing from the spirit and scope thereof, it is intended that all matter shown in the accompanying drawings and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

1. A terminal for use at the discharge end of an expulsion fuse tube and arranged to have con,- nected thereto flexible conductors of replaceable fuse links with or without rigid anchor contact members thereon comprising, a ferrule for receiving one end of the fuse tube, a tongue extending from said ferrule away from its end which receives the fuse tube and having a longitudinal slot at its outer end, a threaded extension at the outer end of said tongue having a. transverse slot therein intersecting said longitudinal slot through which a flexible conductor may be passed or against the outer end of which a rigid anchor contact member on a flexible conductor can react, a nut on said extension, and a jaw movable with said nut and slidable in said transverse slot for clamping the flexible conductor between it and the bottom of the transverse slot.

2. A terminal for use at the discharge end of an expulsion fuse tube and arranged to have connected thereto flexible conductors of replaceable fuse links with or without rigid anchor contact members thereon comprising, a ferrule for receiving one end of the fuse tube, a tongue extending from said ferrule away from its end which receives the fuse tube and having a longitudinal slot at its outer end, and a bifurcated extension at the outer end of said tongu between the prongs of which and in the longitudinal slot a flexible conductor may be passed or against the outer end of which a rigid anchor contact member on a flexible conductor can react, said extension being threaded for receiving a nut to clamp the flexible conductor to the terminal at the bottom of the opening between said prongs.

3. A terminal for use at the discharge end of an expulsion fuse tube and arranged to have conflexible conductors of replaceable or without rigid anchor contact members thereon comprising, a ferrule for receiving one end of the fuse tube, a tongue extending from said ferrule away from its end which receives the fuse tube and having a longitudinal slot at its outer end, and a bifurcated extension constituting a prolongation of the outer end of said tongue between the prongs of which and in the longitudinal slot at flexible conductor can be passed or against the outer ends of which a rigid anchor contact member on a flexible contact member can react, said extension being threaded for receiving a nut to clamp the flexible conductor to the terminal, the front sides of said prongs being slabbed off to provide mechanical clearance between the faces thereof and a nut on said extension in the event that said faces are fused and distorted as a result of heat generated by the are formed on blowing of the fuse link.

4. A terminal for use at the discharge end of an expulsion fuse tube and arranged to have connected thereto flexible conductors of replaceable fuse links with or without rigid anchor contact members thereon comprising, a ferrule for receiving one end of the fuse tube, a tongue exv in ,frorjn "said ferrule away from its end w ic receiyes the fuse tuberand :having a longitudinal slot at its outer end, a threaded extent the outer end of said tongue .having, a

trenisverse; siot therein intersecting said longitudingl slot, through; which a ,oflexibleconductor can be passed; the outer endpf "said threaded extensionb'eing recessed for receiving a rigid anchor member on a flexible conductor, a nut on said extension, and a. jaw movable with said nut and slidghle in Said, transverse slot forvjclam'ping the flexible; conductor between it and. the bottom of stid transverse slot; CARE'E. 'SCHUL'I'HEISS'.

(The following references are of record in tHe file of this patent: V H UNITED STATES PATENTS 

